A prerequisite for meaningful environmental legislation is that it be based upon an adequate scientific understanding of the natural system to which it is applied. In 2003, the Australian Commonwealth and Queensland State governments introduced a Reef Water Quality Protection Plan, which aimed to "improve" water quality in river catchments adjacent to the Great Barrier Reef (GBR) and in nearby coastal waters. The Plan was introduced in the absence of any substantive evidence for regional degradation of GBR water quality. This paper reviews the available data regarding nutrient contents in the Tully River, north Queensland, which is cited as the best (available) evidence for human-related changes in nutrient export from (GBR) catchments(1). It is shown that the claim of human-related nutrient enrichment in the Tully River, and regionally, is without substance. No detectable trends in GBR water quality have occurred since systematic measurements were first started in the 1980s. Environmental policies that are based on mischievous claims of chimerical damage to the Great Barrier Reef damage the reputation of science as a tool for disinterested analysis, and provoke widespread cynicism in the community regarding the integrity of contemporary environmental politics.